Synthesis of bis-2H and 4H-chalcogenapyrans and benzochalcogenapyrans via Pd0 catalyzed dimerization of Fischer type carbene complexes: redox properties and electronic structure of these new extended electron rich molecules - Université de Rennes Accéder directement au contenu
Article Dans Une Revue Tetrahedron Année : 2007

Synthesis of bis-2H and 4H-chalcogenapyrans and benzochalcogenapyrans via Pd0 catalyzed dimerization of Fischer type carbene complexes: redox properties and electronic structure of these new extended electron rich molecules

Résumé

Extended electron rich bis-chalcogenapyrans and bis-benzochalcogenapyrans have been synthesized by Pd0 catalyzed dimerization of α- and γ-methylene chalcogenapyran and benzochalcogenapyran Fischer type carbene complexes. Voltammetric studies performed on these molecules show a single two-electron wave around 0 V versus SCE, which is ascribed to the oxidation of the neutral form in radical and dipyrylium cations. DFT calculations show that the oxidation leads to a rotating movement around the central C-C bond and suggest that the solvent plays a major role in the observation of the two one-electron systems. Furthermore, according to the structure, these molecules are likely to be reduced at very low potential (E=−1.5 V vs SCE) via a two-electron transfer reaction.

Domaines

Chimie organique

Dates et versions

hal-00363438 , version 1 (23-02-2009)

Identifiants

Citer

Nadège Faux, Francoise Robin-Le Guen, Pascal Le Poul, Bertrand Caro, Nicolas Le Poul, et al.. Synthesis of bis-2H and 4H-chalcogenapyrans and benzochalcogenapyrans via Pd0 catalyzed dimerization of Fischer type carbene complexes: redox properties and electronic structure of these new extended electron rich molecules. Tetrahedron, 2007, 63 (30), pp.7142-7153. ⟨10.1016/j.tet.2007.04.099⟩. ⟨hal-00363438⟩
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